C#动态生成json

public class AddModel
{
//AppID（接口提供方提供）
public string appid { get; set; }
//数据Base64加密
public string data { get; set; }
//随机数
public string noise { get; set; }
//版本号
public string version { get; set; }
//秘钥
public string sign { get; set; }
}

string StrSign = StringSign(strData, strNoise);
AddModel addModel = new AddModel();
addModel.appid = strAppid;
addModel.data = strData;
addModel.noise = strNoise;
addModel.version = StrVersion;
addModel.sign = StrSign;
string jsonstr = JsonConvert.SerializeObject(addModel);